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HEPES: Difference between revisions
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Stable pH vs. temperature, no primary amine groups, no metal chelation, near physiologic pH range. HEPES is often used to maintain protein solubility in biochemical experiments. | Stable pH vs. temperature, no primary amine groups, no metal chelation, near physiologic pH range. HEPES is often used to maintain protein solubility in biochemical experiments. | ||
* pK<sub>a</sub> at 25C of 7.55 (7.31 at 37C) | * pK<sub>a</sub> at 25C of 7.55 (7.31 at 37C); (2nd pK<sub>a</sub> at pH 3 is not of interest) | ||
* usable buffering range of 6.8 to 8.2 | * usable buffering range of 6.8 to 8.2 | ||
* molecular weight 238.3 | * molecular weight 238.3 g/mol | ||
* ΔpK<sub>a</sub>/ΔT = -.014 | * ΔpK<sub>a</sub>/ΔT = -.014 | ||
* HEPES contains tertiary amines, which are reactive under certain conditions. | * HEPES contains tertiary amines, which are reactive under certain conditions. | ||
* Chemical formula: C<sub>8</sub>H<sub>18</sub>N<sub>2</sub>O<sub>4</sub>S | * Chemical formula: C<sub>8</sub>H<sub>18</sub>N<sub>2</sub>O<sub>4</sub>S; N-(2-hydroxyethyl)-piperazine-N’-(2-ethanesulfonic acid); aka 4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid; CAS number: 7365-45-9 | ||
Buffers are typically 1 M, prepared by neutralizing HEPES with sodium hydroxide. | Buffers are typically 1 M, prepared by neutralizing HEPES with sodium hydroxide. HEPES is essentially insoluble until it is neutralized. | ||
== 1M HEPES KOH buffer 7.5 == | == 1M HEPES KOH buffer 7.5 == | ||
